1. Technical Field
The present invention relates to an interactive communication system that allows a plurality of subscribers to access a central audiovisual library, more specifically, a system capable of handling each subscriber's tailored requests for program segments.
2. Background of Related Art
Systems which provide subscriber access to prerecorded program segments from a distributor center have been described. For example, in a system described in U.S. Pat. No. 4,521,806 to Abraham, a plurality of subscribers are able independently to access segments of a central program library. The requested broadcast segments are digitized and time compressed at the central station. They are then delivered to the requesting subscriber only. The time compressed segments are recorded at the subscriber station by a two-speed recorder. When the transmission of the requested segment is complete, a broadcast signal attached to the end of the broadcast segment causes the two-speed recorder at the subscriber station to playback immediately the transmitted segment. In this system subscriber viewing time is a function of the program delivery time.
In a system described in U.S. Pat. No. 4,751,684 to Clark et. al., each system subscriber is able to request program segments from a distribution center. These segments are then delivered to all system subscribers indiscriminately. Subscriber requests to the center are placed in line in the chronological order in which they are received, and are broadcast in turn on one common channel.
U.S. Pat. No. 4,963,995 to Lang discloses a video recorder/transmitter apparatus that enables a user to receive, compress, edit, and retransmit video program information in either compressed or decompressed format. The apparatus includes memory for mass data storage. The patent proposes the linkage of a plurality of the apparatus to a network transfer system, with one apparatus acting as a distribution center. The above-mentioned U.S. Pat. Nos. 4,521,806; 4,751,684; and 4,963,995 are incorporated herein by reference.
Other recent audiovisual delivery systems include pay-per-view (PPV) and video-on-demand. Both systems offer real time or near instantaneous delivery of subscriber requested video programs in exchange for fees. Both systems emulate an on premise or home video store. But different from a video program rented from a video store, a drawback of these systems is the inability of the subscriber to manipulate the video program, such as rewind, pause, fast forward, etc., while it is being played or delivered. Further, the fees charged to the subscriber requesting the video program are based on the amount of time the subscriber accesses or is on the system. In contrast, a user who rents video programs from a video store may choose to access the program as many times and whenever he chooses without incurring further charges.
Therefore, there exists a need for an audiovisual delivery system that is efficient for the program distributor while accommodating the individual needs of each subscriber. More particularly, a system capable of handling subscriber requests of several time allowance intervals within which program segments will be delivered. The program distributor accumulates like orders and has the option and capability to fill each of these like orders simultaneously. The subscriber is subsequently able to manipulate and view segments or an entire delivered program.